Composition with improved cleanliness for lubrication of steam and gas turbine systems

ABSTRACT

The present invention relates to the use of an additive composition that contains the combination of two specific types of antioxidants with one or more of four specific types of dispersants in a Group II and/or Group III base oil-containing lubricating composition. The lubricating composition of the present invention provides improved cleanliness in steam and gas turbine systems. The invention further relates to the process to make the novel additive composition and its use in industrial fluids.

FIELD OF THE INVENTION

The present invention relates to the use of an additive composition that contains the combination of two specific types of antioxidants with one or more of four specific types of dispersants in a Group II and/or Group III base oil-containing lubricating composition. The lubricating composition of the present invention provides improved cleanliness in steam and gas turbine systems. The invention further relates to the process to make the novel additive composition and its use in industrial fluids.

BACKGROUND OF THE INVENTION

Varnish is a well known and recognized problem in the lubricant industry and in the area of power generation and gas-turbine applications is becoming of greater and greater concern. Turbine design is moving to systems that provide more power from smaller equipment, leading to tighter clearances, extended drain intervals, and so more stress and harsher conditions on both the equipment and the lubricant used in its operation. The best fluids will meet these challenges and keep the system free of varnish and other deposits. In addition turbine oils are increasingly being formulated with Group II and Group III oils instead of Group I base oils.

These new base oils are much less polar than Group I oils, and additive formulations that worked well in Group I base oils often fail to provide the desired performance when used in Group II and Group III oils. Coupled with the design and operation changes discussed above, there is a need to tailor the additive mixture for optimum performance in Group II and/or Group III base oils.

Group II and Group III oils are more highly refined than Group I oils. Group I oils tend to have higher aromatic and unsaturated components, which are more susceptible to oxidation than other species found in the oils. Indeed, these new groups of oils were developed in part to try and provide improved oxidation stability. While this does provide improved oxidative stability for the base oil itself, they also end up having poorer solvency compared to Group I oils. With this reduced solvency, oxidation by-products, from the oil itself or other sources, that would have remained dissolved in Group I based fluids often drop out of Group II or Group III based fluids, forming varnish on the surfaces of the equipment.

In addition, many power generation turbines in today's market are peaking units, meaning they only operate at times of peak demand. During the regular periods of down time in this type of equipment, when the system lubricant cools, solvency decreases allowing polar materials and varnish to come out of solution and deposit on metal surfaces.

In addition to oxidation and the by-products it produces, static discharge, micro-dieseling, incompatibility, and contamination are also root causes of varnish. Incompatibility is a particular concern with Group II and Group III oils as some additives that are compatible with Group I oils are not compatible with Group II and Group III oils.

Furthermore, Group I based fluids tend to follow gradual oxidation rates that can be monitored over time, giving operators a reliable means of determining the remaining service life of a fluid. In contrast, Group II and Group III based fluids may go from normal oxidation levels and operation to failure mode very quickly with little or no indication before hand. This added complication further increases the need for Group II and Group III based fluids that provide reliable performance in these high cost systems that cannot afford unplanned downtime and equipment damage caused by spent lubricant.

Formulating a fluid with the required amount of oxidative stability and resistance to formation of deposits is a challenge. The primary types of additives used to control oxidation are phenols and amines, both of which react at high temperatures, forming oxidation products that contribute to system deposits and varnish. Thus it is critical to find the proper balance of oxidation inhibitor and dispersant components for the specific application and base fluid involved, allowing for significantly improved lubricant life, and so equipment life and operation time. Dispersants frequently cause oil and water to emulsify, so the choice of the right dispersant must allow the fluid to maintain good demulsibility as required for proper turbine operation. Emulsified water reduces lubricant film formation and promotes rust and oxidation. Fluids that emulsify are not widely accepted in the marketplace.

The formulation of lubricating compositions for steam and gas turbine systems has been complicated by the growing use of API Group II and Group III base oils which has led to increasing varnish formation in some power generating turbines. There is a need for turbine lubricants that allow the use of Group II and Group III base oils while providing long service life, that avoid the varnish problems that can lead to disruptions in equipment operation and unplanned downtime.

It would be desirable for these lubricating oil compositions to be capable of imparting acceptable levels of rust and/or oxidation inhibition without the formation of unwanted deposits that increase the viscosity of the fluid. Furthermore, it would be desirable for these lubricating oil compositions to control and prevent the formation of filter plugging deposits and/or sludge in industrial fluids.

SUMMARY OF THE INVENTION

The invention provides Group II and Group III base oil formulated lubricating compositions for steam and gas turbine systems that provide balanced performance in modern turbine systems. The invention further provides a method of making such compositions and methods of using them in the operation of steam and gas turbine systems.

The invention provides a lubricating oil composition made up of: (a) an oil of lubricating viscosity that includes a Group II base oil, a Group III base oil, or combinations thereof; (b) an antioxidant component; and (c) a dispersant component. The antioxidant component includes: (i) an alkylated diphenylamine, and (ii) a substituted hydrocarbyl mono-sulfide. The dispersant component includes: (i) a polyetheramine; (ii) a borated succinimide dispersant; (iii) a non-borated succinimide dispersant; (iv) a Mannich reaction product of a dialkylamine, an aldehyde and a hydrocarbyl substituted phenol; or any combination thereof. The compositions of the present invention may also include one or more additional additives.

The invention further provides for compositions that further include: (i) a rust inhibitor, for example an amine phosphate, a fatty carboxylic acid or ester thereof, an ester of a nitrogen-containing carboxylic acid, an ammonium sulfonate, or an imidazoline; (ii) a metal deactivator, for example a triazole, a tolyltriazole, a thiadiazole, or combinations thereof; (iii) a demulsifier, for example a polyether; (iv) an antifoam agent, for example an acrylate copolymer; or any combinations thereof.

The invention further provides for compositions that include a substituted hydrocarbyl mono-sulfide. In other embodiments the invention provides for compositions essentially free or even free of substituted hydrocarbyl mono-sulfides.

The invention provides for the compositions described above where the dispersant component includes a polyetheramine derived from the reaction of a mixture of alcohols containing from 10 to 18 carbon atoms, an alkylene oxide and an amine; wherein the antioxidant component is present in the overall composition at less than 0.865 parts by weight; wherein the composition is free of N-alkyl sarcosines; wherein the composition contains less than 0.1 parts by weight of fatty carboxylic acids; and wherein the dispersant component is present in the overall composition from 0.07 to 0.4 parts by weight.

The invention provides for the compositions described above where the dispersant component includes a borated succinimide dispersant derived from polyisobutylene having a number average molecular weight from 500 to 3000 and polyethylenepolyamines; wherein the dispersant component is present in the overall composition from 0.07 to less than 0.4 parts by weight.

The invention provides for the compositions described above where the dispersant component includes a non-borated succinimide dispersant derived from polyisobutylene having a number average molecular weight from 500 to 3000 and polyethylenepolyamines; wherein the composition contains less than 0.1 parts by weight of fatty carboxylic acids; and wherein the dispersant component is present in the overall composition from 0.06 to 0.35 parts by weight.

The invention provides for the compositions described above where the dispersant component includes a Mannich reaction product derived from the reaction of a dialkylamine, formaldehyde, and a polyisobutylene substituted phenol where the polyisobutylene has a number average molecular weight from 500 to 3000; and wherein the dispersant component is present in the overall composition from 0.07 to 0.44 parts by weight.

The process of the invention, wherein the antioxidant package is in the range of 0.05 to 13 parts be weight of the overall composition; the dispersant component is in the range of 0.05 to 10 parts be weight of the overall composition; the optional additives, when present, are present from 0.001 to 10 parts be weight of the overall composition; and the balance is made up of the oil of lubricating viscosity.

The invention provides for a process of making the lubricating compositions described herein including the steps of mixing together the components described above, and further described below.

The invention further provides a lubricating oil composition that is capable of preventing filter plugging deposits and sludge.

DETAILED DESCRIPTION OF THE INVENTION

Various features and embodiments of the invention will be described below by way of non-limiting illustration. Unless otherwise noted, the part by weight (pbw) values provided herein for various components described below are in regards to compositions that contain 100 pbw base oil. However the pbw values may, in some embodiments, instead be treated as percent by weight values relative to an overall composition.

The invention provides a lubricating oil composition made up of: (a) an oil of lubricating viscosity that includes a Group II base oil, a Group III base oil, or combinations thereof; (b) an antioxidant component; and (c) a dispersant component. The antioxidant component includes: (i) an alkylated diphenylamine, and (ii) a substituted hydrocarbyl mono-sulfide. The dispersant component includes: (i) a polyetheramine; (ii) a borated succinimide dispersant; (iii) a non-borated succinimide dispersant; (iv) a Mannich reaction product of a dialkylamine, an aldehyde and a hydrocarbyl substituted phenol; or any combination thereof. The compositions of the present invention may also include one or more additional additives.

The Oil of Lubricating Viscosity

One component of the compositions of the invention is an oil of lubricating viscosity, which can be present in a major amount, for a lubricant composition, or in a concentrate forming amount, for a concentrate. Suitable oils include natural and synthetic lubricating oils and mixtures thereof. In a fully formulated lubricant, the oil of lubricating viscosity is generally present in a major amount (i.e. an amount greater than 50 percent by weight). Typically, the oil of lubricating viscosity is present in an amount of 75 to 95 percent by weight, and often greater than 80 percent by weight of the overall composition. The base oil component generally makes up 100 parts by weight (pbw) of the overall composition with the pbw ranges for the other components being provided with this 100 pbw of base oil in mind. In other embodiments the pbw ranges of the various components, including the base oils, are provided such that the total of the pbw of all components is 100. The pbw ranges provided for the various components described below may be taken either way.

The lubricating oil component of the present invention includes a Group II or Group III base oil, or a combination thereof. These are classifications established by the API (American Petroleum Institute). Group III oils contain <0.03 percent sulfur and >90 percent saturates and have a viscosity index of >120. Group II oils have a viscosity index of 80 to 120 and contain <0.03 percent sulfur and >90 percent saturates. The oil can also be derived from the hydroisomerization of wax, such as slack wax or a Fischer-Tropsch synthesized wax. Such “Gas-to-Liquid” oils are typically characterized as Group III.

The compositions of the present invention may include some amount of Group I base oils, and even Group IV and Group V base oils. Polyalphaolefins are categorized as Group IV. Group V encompasses “all others”. However, in some embodiments the lubricating oil component of the invention contains no more than 20, 10, 5, or even 1 percent by weight Group I base oil. These limits may also apply to Group IV or Group V base oils. In other embodiments the lubricating oil present in the compositions of the invention is at least 60, 70, 80, 90, or even 95 percent by weight Group II and/or Group III base oil. In some embodiments the lubricating oil present in the compositions of the invention is essentially only Group II and/or Group III base oil, where small amounts of other types of base oils may be present but not in amounts that significantly impact the properties or performance of the overall composition.

The oil of lubricating viscosity may be present in the range from 60 to 99.9, from 88.5 to 99.6, from 96.9 to 99.5, or from 98.2 to 99.4 weight percent of the lubricating oil composition. Each oil of lubricating viscosity described above may be used alone or as mixtures of one or more thereof.

The Antioxidant Component

The antioxidant component includes: (i) an alkylated diphenylamine, and (ii) a substituted hydrocarbyl mono-sulfide.

The alkylated diphenylamines suitable for use in the invention may be represented by the formula:

wherein R¹ and R² are independently a hydrogen or an alkyl group containing about 5 to 20 carbon atoms; or a linear or branched alkyl group containing 1 to 24 carbon atoms and q and r are each independently 0, 1, 2, or 3, provided that the sum of q and r is at least one. In some embodiments R¹ and R² are independently hydrogen or alkyl groups containing 1 to 24, 4 to 20, 5 to 16, or 6 to 12 or even 10 carbon atoms. In any of the embodiments described above, each R¹ and R² may be a linear alkyl group, a branched alkyl group, or even an arylalkyl group.

In some embodiments the alkylated diphenylamines of the invention are bis-nonylated diphenylamine and bis-octylated diphenylamine.

The alkylated diphenylamines are present in a range from 0.02 to 4, from 0.03 to 2.5, or from 0.05 to 1.5 pbw of the overall lubricating composition. In some embodiments the alkylated diphenylamines are present in a range from 0.01, 0.05, 0.10, 0.15, 0.20, 0.25, 0.3, or even 0.35 up to 1.0, 0.9, 0.8, 0.75, 0.7, or even 0.6 pbw of the overall lubricating composition. In still other embodiments the alkylated diphenylamines may be present from 0.35 or 0.375 up to 0.51, 0.75, 0.775 or 0.1 pbw of the overall lubricating composition, or even 0.375 pbw. The alkylated diphenylamines may be used alone or in mixtures thereof.

The substituted hydrocarbyl mono-sulfides suitable for use in the invention may be represented by the formula:

wherein R³ is a saturated or unsaturated branched or linear alkyl group with about 8 to about 20 carbon atoms; R⁴, R⁵, R⁶ and R⁷ are independently hydrogen or alkyl containing about 1 to about 3 carbon atoms, or even 1 to 2 carbon atoms. In some embodiments R³ contains from 8 to 20, 9 to 17, 10 to 15 or even 11 to 13 carbon atoms. R³ can be branched or linear, but in some embodiments is branched.

In some embodiments the substituted hydrocarbyl monosulfides include n-dodecyl-2-hydroxyethyl sulfide, 1-(tert-dodecylthio)-2-propanol, or combinations thereof. In some embodiments the substituted hydrocarbyl monosulfide is 1-(tert-dodecylthio)-2-propanol.

The substituted hydrocarbyl monosulfides may be present in the range from 0.02 to 4, 0.03 to 2.5, or 0.05 to 1.5 pbw of the lubricating oil composition. In some embodiments the substituted hydrocarbyl monosulfides are present in a range from 0.01, 0.03, 0.05, or even 0.08 up to 1.0, 0.8, 0.5, 0.3 or 0.1 pbw of the overall lubricating composition. In still other embodiments the substituted hydrocarbyl monosulfides may be present from 0.08 up to 0.1, or even at 0.09 pbw of the overall lubricating composition. The substituted hydrocarbyl monosulfides may be used alone or mixtures thereof.

The antioxidant package may optionally include sterically hindered phenols represented by the formula:

wherein R⁸ and R⁹ are independently branched or linear alkyl groups containing about 1 to about 24, preferably about 4 to about 18, and most preferably from about 4 to about 12 carbon atoms.

R⁸ and R⁹ may be either a straight or branched chain, branched is preferred. Preferably the phenol is butyl substituted containing two t-butyl groups. When the t-butyl groups occupy the 2,6-positions, the phenol is sterically hindered. q is hydrogen or hydrocarbyl. Examples of suitable hydrocarbyl groups include but are not limited to 2-ethylhexyl or n-butyl ester, dodecyl or mixtures thereof.

Other optional sterically hindered phenols suitable for the invention include but are not limited to those represented by the formulae:

wherein R¹⁰, R¹¹, R¹², R¹³, R¹⁴, R¹⁵ are either straight or branched chain and contain about 4 to about 18, preferably from about 4 to about 12 carbon atoms. Preferably the phenol is butyl substituted.

R¹⁶ and R¹⁷ are independently hydrogen, an arylalkyl group or a linear or branched alkyl group. R¹⁶ and R¹⁷ are preferably in the para position. The arylalkyl or alkyl groups contain about 1 to about 15, preferably about 1 to about 10, and most preferably about 1 to about 5 carbon atoms. The bridging group Y includes but is not limited to —CH₂— (methylene bridge) or —CH₂OCH₂— (ether bridge).

Examples of methylene-bridged sterically hindered phenols include but are not limited to 4,4′-methylenebis(6-tert-butyl o-cresol), 4,4′-methylenebis(2-tert-amyl-o-cresol), 2,2′-methylenebis(4-methyl-6-tert-butylphenol), 4,4′-methylenebis(2,6-di-tertbutylphenol) or mixtures thereof.

In one embodiment the antioxidant is a hindered ester-substituted phenol represented by the formula:

wherein R¹⁸, R¹⁹ and R²⁰ are straight or branched alkyl group containing about 2 to about 22, preferably about 2 to about 18, more preferably about 4 to about 8 carbon atoms. Specific examples include but are not limited to alkyl groups such as 2-ethylhexyl or n-butyl ester, dodecyl or mixtures thereof.

The sterically hindered phenols are present in the range from 0 to 13, from 0.02 to 4, from 0.03 to 2.5, or from 0.05 to 1.5 pbw of the lubricating oil composition. The sterically hindered phenols may be used alone or in combination. In some embodiments the compositions of the invention are essentially free or even free of sterically hindered phenols.

In some embodiments the antioxidant component, whether it contains one antioxidant or a mixture of two or more antioxidants, may be present in the overall composition from 0.05 to 13 pbw, or from 0.1 to 0.4 pbw, or from 0.05, 0.1, 0.2, or 0.3 up to 13, 0.9, 0.75, 0.6, or 0.5 pbw. In some embodiments the antioxidant component is even present from 0.4 up to 0.9 or 0.5 pbw. In other embodiments the antioxidant component is present from 0.45, 0.465, or even 0.60 up to 0.87, 0.865, 0.70 or 0.65 pbw.

The Dispersant Component

The dispersant component includes: (i) a polyetheramine; (ii) a borated succinimide dispersant; (iii) a non-borated succinimide dispersant; (iv) a Mannich reaction product of a dialkylamine, an aldehyde and a hydrocarbyl substituted phenol; or any combination thereof. In some embodiments the dispersant component is present from 0.05 to 0.5 pbw of the overall composition.

Polyetheramines of the invention include compounds having two or more consecutive ether groups and at least one primary, secondary or tertiary amino group where the amine nitrogen has some basicity. The polyetheramines of this invention include poly(oxyalkylene) amines having a sufficient number of repeating oxyalkylene units to render the poly(oxyalkylene)amine soluble in a base oil while allowing acceptable performance in ASTM D1401 (Standard Test Method for Water Separability of Petroleum Oils and Synthetic Fluids) test. Generally, poly(oxyalkylene)amines having at least about 5 oxyalkylene units are suitable for use in the present invention. Poly(oxyalkylene)amines can include: hydrocarbylpoly(oxyalkylene)amines, hydrocarbylpoly(oxyalkylene)polyamines, and derivatives of polyhydric alcohols having at least two poly(oxyalkylene)amine and/or poly(oxyalkylene)polyamine chains on the molecule of the derivative. In one embodiment, the poly(oxyalkylene)amine for use in the invention is represented by the formula R—O-(AO)_(m)—R¹—N—R²R³ wherein R is a hydrocarbyl group of 1 to 50 carbon atoms, or about 8 to about 30 carbon atoms; A is an alkylene group having 2 to 18 carbon atoms or 2 to 6 carbon atoms; m is a number from 1 to 50; R¹ is an alkylene group having 2 to 18 carbon atoms or 2 to 6 carbon atoms; and R² and R³ are independently hydrogen, a hydrocarbyl group or —[R⁴N(R⁵)]_(n)R⁶ wherein R⁴ is an alkylene group having 2 to 6 carbon atoms, R⁵ and R⁶ are independently hydrogen or a hydrocarbyl group, and n is a number from 1 to 7.

In another embodiment, the poly(oxyalkylene)amine of the present invention can be represented by the formula: RO[CH₂CH(CH₂CH₃)O]_(m)CH₂CH₂CH₂NH₂ wherein R is an aliphatic group or alkyl-substituted phenyl group of 8 to 30 carbon atoms; and m is a number from 12 to 30. In yet another embodiment, the poly(oxyalkylene)amine of the present invention can be represented by the formula: CH₃CH(CH₃)[CH₂CH(CH₃)]₂CH(CH₃)CH₂CH₂O—[CH₂CH(CH₂CH₃)O]_(m)CH₂CH₂CH₂NH₂ wherein m is a number from about 16 to about 28. Poly(oxyalkylene)amines of the present invention can have a molecular weight in the range from about 300 to about 5,000.

The polyetheramines of the present invention can be prepared by initially condensing an alcohol or alkylphenol with an alkylene oxide, mixture of alkylene oxides or with several alkylene oxides in sequential fashion in a 1:1-50 mole ratio of hydric compound to alkylene oxide to form a polyether intermediate. U.S. Pat. Nos. 5,112,364 and 5,264,006 provide reaction conditions for preparing a polyether intermediate.

The alcohols can be monohydric or polyhydric, linear or branched, saturated or unsaturated and having 1 to 50 carbon atoms, or from 8 to 30 carbon atoms, or from 10 to 16 carbon atoms. Branched alcohols of the present invention can include Guerbet alcohols, as described in U.S. Pat. No. 5,264,006, which generally contain between 12 and 40 carbon atoms and can be represented by the formula R—CH(CH₂CH₂R)CH₂OH where R is a hydrocarbyl group. In one embodiment, the alkyl group of the alkylphenols can be 1 to 50 carbon atoms, or 2 to 24 carbon atoms, or 10 to 20 carbon atoms.

In one embodiment, the alkylene oxides include 1,2-epoxyalkanes having 2 to 18 carbon atoms, or 2 to 6 carbon atoms. In yet another embodiment, the alkylene oxides can be ethylene oxide, propylene oxide and butylene oxide. Especially useful is propylene oxide, butylene oxide, or a mixture thereof. The number of alkylene oxide derived units in the polyether intermediate can be 1-50, or 12-30, or 16-28.

The polyether intermediates can be converted to polyetheramines by several methods. The polyether intermediate can be converted to a polyetheramine by a reductive amination with ammonia, a primary amine or a polyamine as described in U.S. Pat. Nos. 5,112,364 and 5,752,991. In one embodiment, the polyether intermediate can be converted to a polyetheramine via an addition reaction of the polyether to acrylonitrile to form a nitrile which is then hydrogenated to form the polyetheramine. U.S. Pat. No. 5,264,006 provides reaction conditions for the cyanoethylation of the polyether with acrylonitrile and the subsequent hydrogenation to form the polyetheramine. In yet another embodiment, the polyether intermediate or poly(oxyalkylene) alcohol is converted to the corresponding poly(oxyalkylene) chloride via a suitable chlorinating agent followed by displacement of chlorine with ammonia, a primary or secondary amine, or a polyamine as described in U.S. Pat. No. 4,247,301.

In some embodiments the polyetheramine of the present invention is derived from the reaction of a mixture of alcohols containing from 10 to 18 carbon atoms, an alkoxylate and an amine.

In some embodiments the compositions of the present invention include a polyetheramine dispersant where the polyetheramine is present in the overall composition from 0.07 to 0.6 pbw, or from 0.09 to 0.5 pbw.

In addition, in some of these embodiments, (i) the antioxidant component is present in the overall composition at less than 0.865 pbw; (ii) the composition is free of N-alkyl sarcosines; (iii) the composition contains less than 0.15 pbw of fatty carboxylic acids; or any combination thereof.

Another type of dispersant, which can be used in the invention, is a succinimide. Succinimide dispersants are well known in the field of lubricants and include primarily what are sometimes referred to as “ashless” dispersants because they do not contain ash-forming metals and they do not normally contribute any ash forming metals when added to a lubricant. Succinimide dispersants are the reaction product of a hydrocarbyl substituted succinic acylating agent and an amine containing at least one hydrogen attached to a nitrogen atom. The term “succinic acylating agent” refers to a hydrocarbon-substituted succinic acid or succinic acid-producing compound (which term also encompasses the acid itself). Such materials typically include hydrocarbyl-substituted succinic acids, anhydrides, esters (including half esters) and halides.

Succinic based dispersants have a wide variety of chemical structures including typically structures such as:

In the above structure, each R¹ is independently a hydrocarbyl group, which may be bound to multiple succinimide groups, typically a polyolefin-derived group having a number average molecular weight (Mn) of 500 or 700 to 10,000. Typically the hydrocarbyl group is an alkyl group, frequently a polyisobutylene group derived from polyisobutylene with a Mn of 500 or 700 to 5000, or 1500 or 2000 to 5000. Alternatively expressed, the R¹ groups can contain 40 to 500 carbon atoms or at least 50 to 300 carbon atoms, e.g., aliphatic carbon atoms. The R² are alkylene groups, commonly ethylene (C₂H₄) groups. Such molecules are commonly derived from reaction of an alkenyl acylating agent with a polyamine, and a wide variety of linkages between the two moieties is possible beside the simple imide structure shown above, including a variety of amides and quaternary ammonium salts. Succinimide dispersants are more fully described in U.S. Pat. Nos. 4,234,435, 3,172,892, and 6,165,235.

The polyalkenes from which the substituent groups are derived are typically homopolymers and interpolymers of polymerizable olefin monomers of 2 to 16 carbon atoms; usually 2 to 6 carbon atoms.

The olefin monomers from which the polyalkenes are derived are polymerizable olefin monomers characterized by the presence of one or more ethylenically unsaturated groups (i.e., >C═C<); that is, they are mono-olefinic monomers such as ethylene, propylene, 1-butene, isobutene, and 1-octene or polyolefinic monomers (usually diolefinic monomers) such as 1,3-butadiene, and isoprene. These olefin monomers are usually polymerizable terminal olefins; that is, olefins characterized by the presence in their structure of the group >C═CH₂. Relatively small amounts of non-hydrocarbon substituents can be included in the polyolefin, provided that such substituents do not substantially interfere with formation of the substituted succinic acid acylating agents. Each R¹ group may contain one or more reactive groups, i.e. succinic groups.

The amines which are reacted with the succinic acylating agents to form the carboxylic dispersant composition can be monoamines or polyamines. In either case they will be characterized by the formula R⁴R⁵NH wherein R⁴ and R⁵ are each independently hydrogen, hydrocarbon, amino-substituted hydrocarbon, hydroxy-substituted hydrocarbon, alkoxy-substituted hydrocarbon, amino, carbamyl, thiocarbamyl, guanyl, or acylimidoyl groups provided that no more than one of R⁴ and R⁵ is hydrogen. In all cases, therefore, they will be characterized by the presence within their structure of at least one H—N<group. Therefore, they have at least one primary (i.e., H₂N—) or secondary amino (i.e., H—N<) group. Examples of monoamines include ethylamine, diethylamine, n-butylamine, di-n-butylamine, allylamine, isobutylamine, cocoamine, stearylamine, laurylamine, methyllaurylamine, oleylamine, N-methyl-octylamine, dodecylamine, and octadecylamine.

The polyamines from which the dispersant is derived include principally alkylene amines conforming, for the most part, to the formula

wherein t is an integer typically less than 10, A is hydrogen or a hydrocarbyl group typically having up to 30 carbon atoms, and the alkylene group is typically an alkylene group having less than 8 carbon atoms. The alkylene amines include principally, ethylene amines, hexylene amines, heptylene amines, octylene amines, other polymethylene amines. They are exemplified specifically by: ethylene diamine, diethylene triamine, triethylene tetramine, propylene diamine, decamethylene diamine, octamethylene diamine, di(heptamethylene) triamine, tripropylene tetramine, tetraethylene pentamine, trimethylene diamine, pentaethylene hexamine, di(-trimethylene) triamine. Higher homologues such as are obtained by condensing two or more of the above-illustrated alkylene amines likewise are useful. Tetraethylene pentamine is particularly useful.

The ethylene amines, also referred to as polyethylene polyamines, are especially useful. They are described in some detail under the heading “Ethylene Amines” in Encyclopedia of Chemical Technology, Kirk and Othmer, Vol. 5, pp. 898-905, Interscience Publishers, New York (1950).

Hydroxyalkyl-substituted alkylene amines, i.e., alkylene amines having one or more hydroxyalkyl substituents on the nitrogen atoms, likewise are useful. Examples of such amines include N-(2-hydroxyethyl)ethylene diamine, N,N′-bis(2-hydroxyethyl)-ethylene diamine, 1-(2-hydroxyethyl)piperazine, monohydroxy-propyl)-piperazine, di-hydroxypropyl-substituted tetraethylene pentamine, N-(3-hydroxypropyl)-tetra-methylene diamine, and 2-heptadecyl-1-(2-hydroxyethyl)-imidazoline.

Higher homologues, such as are obtained by condensation of the above-illustrated alkylene amines or hydroxy alkyl-substituted alkylene amines through amino radicals or through hydroxy radicals, are likewise useful. Condensed polyamines are formed by a condensation reaction between at least one hydroxy compound with at least one polyamine reactant containing at least one primary or secondary amino group and are described in U.S. Pat. No. 5,230,714 (Steckel).

The succinimide dispersant is referred to as such since it normally contains nitrogen largely in the form of imide functionality, although it may be in the form of amine salts, amides, imidazolines as well as mixtures thereof. To prepare the succinimide dispersant, one or more of the succinic acid-producing compounds and one or more of the amines are heated, typically with removal of water, optionally in the presence of a normally liquid, substantially inert organic liquid solvent/diluent at an elevated temperature, generally in the range of 80° C. up to the decomposition point of the mixture or the product; typically 100° C. to 300° C.

The succinic acylating agent and the amine (or organic hydroxy compound, or mixture thereof) are typically reacted in amounts sufficient to provide at least one-half equivalent, per equivalent of acid-producing compound, of the amine (or hydroxy compound, as the case may be). Generally, the maximum amount of amine present will be about 2 moles of amine per equivalent of succinic acylating agent. For the purposes of this invention, an equivalent of the amine is that amount of the amine corresponding to the total weight of amine divided by the total number of nitrogen atoms present. The number of equivalents of succinic acid-producing compound will vary with the number of succinic groups present therein, and generally, there are two equivalents of acylating reagent for each succinic group in the acylating reagents. Additional details and examples of the procedures for preparing the succinimide detergents of the present invention are included in, for example, U.S. Pat. Nos. 3,172,892; 3,219,666; 3,272,746; 4,234,435; 6,440,905 and 6,165,235.

In some embodiments the compositions of the invention include a non-borated succinimide dispersant derived from polyisobutylene having a number average molecular weight from 500 to 3000 and polyethylenepolyamines.

In such embodiments the non-borated succinimide dispersant may be present in the overall composition from 0.06 to 0.35 pbw, or from 0.05, 0.06, 0.055, 0.065, or even 0.057 up to 0.5, 0.35, 0.33, 0.325, or even 0.285 pbw. In some embodiments the non-borated succinimide dispersant is present from 0.057 to 0.285 pbw. In other embodiments the non-borated succinimide dispersant is present from 0.057 to 0.325 pbw.

In some of these embodiments the composition contains less than 0.1 pbw of fatty carboxylic acids.

In some embodiments the succinimide dispersants above may be borated. Borated dispersants are well-known materials and can be prepared by treating one or more of dispersants described above with a borating agent such as boric acid. Typical conditions include heating the dispersant with boric acid at 100 to 150 degrees C. The dispersants may also be treated by reaction with maleic anhydride as described in PCT application US99/23940 filed 13 Oct. 1999.

In some embodiments the compositions of the invention include a borated succinimide dispersant derived from polyisobutylene having a number average molecular weight from 500 to 3000 and polyethylenepolyamines.

In such embodiments the borated succinimide dispersant may be present in the overall composition from 0.07 to 0.4 pbw, or from 0.05, 0.07, or even 0.067 up to 0.5, 0.4, 0.35 or even 0.335 pbw.

In some of these embodiments the composition contains less than 0.1 pbw of fatty carboxylic acids.

The dispersant of the invention can be a Mannich dispersant. Mannich dispersants are the reaction product of a hydrocarbyl-substituted phenol, an aldehyde, and an amine or ammonia, but in this invention generally a dialkylamine. The hydrocarbyl substituent of the hydrocarbyl-substituted phenol can have 10 to 400 carbon atoms, in another instance 30 to 180 carbon atoms, and in a further instance 10 or 40 to 110 carbon atoms. This hydrocarbyl substituent can be derived from an olefin or a polyolefin. Useful olefins include alpha-olefins, such as 1-decene, which are commercially available.

The polyolefins which can form the hydrocarbyl substituent can be prepared by polymerizing olefin monomers by well known polymerization methods and are also commercially available. The olefin monomers include monoolefins, including monoolefins having 2 to 10 carbon atoms such as ethylene, propylene, 1-butene, isobutylene, and 1-decene. An especially useful monoolefin source is a C₄ refinery stream having a 35 to 75 weight percent butene content and a 30 to 60 weight percent isobutene content. Useful olefin monomers also include diolefins such as isoprene and 1,3-butadiene. Olefin monomers can also include mixtures of two or more monoolefins, of two or more diolefins, or of one or more monoolefins and one or more diolefins. Useful polyolefins include polyisobutylenes having a number average molecular weight of 140 to 5000, in another instance of 400 to 2500, and in a further instance of 140 or 500 to 1500. The polyisobutylene can have a vinylidene double bond content of 5 to 69 percent, in a second instance of 50 to 69 percent, and in a third instance of 50 to 95 percent. The polyolefin can be a homopolymer prepared from a single olefin monomer or a copolymer prepared from a mixture of two or more olefin monomers. Also possible as the hydrocarbyl substituent source are mixtures of two or more homopolymers, two or more copolymers, or one or more homopolymers and one or more copolymers.

The hydrocarbyl-substituted phenol can be prepared by alkylating phenol with an olefin or polyolefin described above, such as a polyisobutylene or polypropylene, using well-known alkylation methods.

The aldehyde used to form the Mannich dispersant can have 1 to 10 carbon atoms, and is generally formaldehyde or a reactive equivalent thereof such as formalin or paraformaldehyde.

The amine used to form the Mannich dispersant can be a monoamine or a polyamine, including alkanolamines having one or more hydroxyl groups. Useful amines include ethanolamine, diethanolamine, methylamine, dimethylamine, ethylenediamine, dimethylaminopropylamine, diethylenetriamine and 2-(2-amino-ethylamino) ethanol. The Mannich dispersant can be prepared by reacting a hydrocarbyl-substituted phenol, an aldehyde, and an amine as described in U.S. Pat. No. 5,697,988. In one embodiment of this invention the Mannich reaction product is prepared from an alkylphenol derived from a polyisobutylene, formaldehyde, and an amine that is a primary monoamine, a secondary monoamine, or an alkylenediamine, in particular, ethylenediamine or dimethylamine. In some embodiments the Mannich is prepared from a dialkylamine or a dialkenylamine.

The Mannich reaction product of the present invention can be prepared by reacting the alkyl-substituted hydroxyaromatic compound, aldehyde and polyamine by well known methods including the method described in U.S. Pat. No. 5,876,468.

The Mannich reaction product can be prepared by well known methods generally involving reacting the hydrocarbyl substituted hydroxy aromatic compound, an aldehyde and an amine at temperatures between 50 to 200° C. in the presence of a solvent or diluent while removing reaction water as described in U.S. Pat. No. 5,876,468.

In some embodiments the compositions of the present invention contain a Mannich reaction product derived from the reaction of a dialkylamine, formaldehyde, and a polyisobutylene substituted phenol where the polyisobutylene has a number average molecular weight from 500 to 3000. The Mannich dispersant may be present in the overall composition from 0.07 to 0.44 pbw, from 0.05, 0.07, or even 0.088 up to 0.5, 0.45, or even 0.44 pbw.

Additional Additives

Optionally the lubricating compositions of the invention include one or more additional additives, which may be selected from the group including: a foam inhibitor, a demulsifier, a pour point depressant, or mixtures thereof. The optional additives are present in the range from 0.0005 to 1.3, from 0.00075 to 0.5, from 0.001 to 0.4, or from 0.0015 to 0.3 pbw of the lubricating oil composition. The optional additives may be used alone or mixtures thereof.

Antifoams, also known as foam inhibitors, are known in the art and include but are not limited to organic silicones and non-silicon foam inhibitors. Examples of organic silicones include dimethyl silicone and polysiloxanes. Examples of non-silicon foam inhibitors include but are not limited to poly(ethyl acrylate), poly(2-ethylhexylacrylate), copolymers of ethyl acrylate and 2-ethylhexy acrylate and optionally vinyl acetate, poly vinyl acetate, polyethers, polyacrylates and mixtures thereof. In some embodiments the antifoam is a polyacrylate. Antifoams may be present in the composition from 0.001 to 0.012 or 0.004 pbw or even 0.001 to 0.003.

Demulsifiers are known in the art and include but are not limited to derivatives of propylene oxide, ethylene oxide, polyoxyalkylene alcohols, alkyl amines, amino alcohols, diamines or polyamines reacted sequentially with ethylene oxide or substituted ethylene oxides or mixtures thereof. Examples of demulsifiers include polyethylene glycols, polyethylene oxides, polypropylene oxides, (ethylene oxide-propylene oxide) polymers and mixtures thereof. In some embodiments the demulsifiers is a polyether. Demulsifiers may be present in the composition from 0.002 to 0.012 pbw.

Pour point depressants are known in the art and include but are not limited to esters of maleic anhydride-styrene copolymers, polymethacrylates; polyacrylates; polyacrylamides; condensation products of haloparaffin waxes and aromatic compounds; vinyl carboxylate polymers; and terpolymers of dialkyl fumarates, vinyl esters of fatty acids, ethylene-vinyl acetate copolymers, alkyl phenol formaldehyde condensation resins, alkyl vinyl ethers and mixtures thereof.

The compositions of the invention may also include a rust inhibitor. Suitable rust inhibitors include hydrocarbyl amine salts of alkylphosphoric acid, hydrocarbyl amine salts of dialkyldithiophosphoric acid, hydrocarbyl amine salts of hydrocarbyl aryl sulphonic acid, fatty carboxylic acids or esters thereof, an ester of a nitrogen-containing carboxylic acid, an ammonium sulfonate, an imidazoline, or any combination thereof; or mixtures thereof.

Suitable hydrocarbyl amine salts of alkylphosphoric acid of the invention are represented by the following formula:

wherein R²¹ and R²² are independently hydrogen, alkyl chains or hydrocarbyl, preferably at least one of R²¹ and R²² are hydrocarbyl. R²¹ and R²² contain about 4 to about 30, preferably about 8 to about 25, more preferably about 10 to about 20, and most preferably about 13 to about 19 carbon atoms. R²³, R²⁴ and R²⁵ are independently hydrogen, alkyl branched or linear alkyl chains with about 1 to about 30, preferably about 4 to about 24, even more preferably about 6 to about 20, and most preferably about 10 to about 16 carbon atoms. R²³, R²⁴ and R²⁵ are independently hydrogen, alkyl branched or linear alkyl chains, preferably at least one, and most preferably two of R²³, R²⁴ and R²⁵ are hydrogen.

Examples of alkyl groups suitable for R²³, R²⁴ and R²⁵ include but are not limited to butyl, sec butyl, isobutyl, tert-butyl, pentyl, n-hexyl, sec hexyl, n-octyl, 2-ethyl, hexyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, octadecenyl, nonodecyl, eicosyl or mixtures thereof.

In one embodiment the hydrocarbyl amine salt of an alkylphosphoric acid is the reaction product of a C₁₄ to C₁₈ alkylated phosphoric acid with Primene 81R (produced and sold by Rohm & Haas) which is a mixture of C₁₁ to C₁₄ tertiary alkyl primary amines.

Hydrocarbyl amine salts of dialkyldithiophosphoric acid of the invention used in the rust inhibitor package are represented by the formula:

wherein R²⁶ and R²⁷ are independently branched or linear alkyl groups. R²⁶ and R²⁷ contain about 3 to about 30, preferably about 4 to about 25, more preferably about 5 to about 20, and most preferably about 6 to about 19 carbon atoms. R²³, R²⁴ and R²⁵ are as described above.

Examples of hydrocarbyl amine salts of dialkyldithiophosphoric acid of the invention include but are not limited to the reaction product(s) of heptylated or octylated or nonylated dithiophosphoric acids with ethylene diamine, morpholine or Primene 81R or mixtures thereof.

Suitable hydrocarbyl amine salts of hydrocarbyl aryl sulphonic acids used in the rust inhibitor package of the invention are represented by the formula:

wherein Cy is a benzene or naphthalene ring. R²⁸ is a hydrocarbyl group with about 4 to about 30, preferably about 6 to about 25, more preferably about 8 to about 20 carbon atoms. z is independently 1, 2, 3, or 4 and most preferably z is 1 or 2. R²³, R²⁴ and R²⁵ are as described above.

Examples of hydrocarbyl amine salts of hydrocarbyl aryl sulphonic acid of the invention include but are not limited to the ethylene diamine salt of dinonyl naphthalene sulphonic acid.

Examples of suitable fatty carboxylic acids or esters thereof include glycerol monooleate and oleic acid. An example of a suitable ester of a nitrogen-containing carboxylic acid includes oleyl sarcosine.

The rust inhibitors may be present in the range from 0.02-0.2, from 0.03 to 0.15, from 0.04 to 0.12, or from 0.05 to 0.1 pbw of the lubricating oil composition. The rust inhibitors of the invention may be used alone or in mixtures thereof.

The lubricating compositions of the invention may also include a metal deactivator. Metal deactivators are used to neutralise the catalytic effect of metal for promoting oxidation in lubricating oil. Suitable metal deactivators include but are not limited to triazoles, tolyltriazoles, a thiadiazole, or combinations thereof, as well as derivatives thereof. Examples include derivatives of benzotriazoles, benzimidazole, 2-alkyldithiobenzimidazoles, 2-alkyldithiobenzothiazoles, 2-(N,N′-dialkyldithio-carbamoyl)benzothiazoles, 2,5-bis(alkyl-dithio)-1,3,4-thiadiazoles, 2,5-bis(N,N′-dialkyldithiocarbamoyl)-1,3,4-thiadiazoles, 2-alkyldithio-5-mercapto thiadiazoles or mixtures thereof.

In some embodiments the metal deactivator is a hydrocarbyl substituted benzotriazole compound. The benzotriazole compounds with hydrocarbyl substitutions include at least one of the following ring positions 1- or 2- or 4- or 5- or 6- or 7-benzotriazoles. The hydrocarbyl groups contain about 1 to about 30, preferably about 1 to about 15, more preferably about 1 to about 7 carbon atoms, and most preferably the metal deactivator is 5-methylbenzotriazole used alone or mixtures thereof.

In some embodiments the lubricating compositions on the invention include a substituted triazole, and may be a substituted benzotriazole. In some of these embodiments the hydrocarbyl group linked to one of the nitrogen atoms in the triazole ring does not contain any oxygen atoms.

In some embodiments the substituted triazole has a single hydrocarbyl group linked to a nitrogen atom on the triazole ring. In some embodiments the substituted triazole contains an aryl group linked and a single hydrocarbyl group linked to a nitrogen atom on the triazole ring.

In some embodiments the substituted triazole may be represented by the following formulas:

or a combination thereof; where, for both formula X and formula XI: n is an integer from 0 to 4; —R is a hydrocarbyl group; —Y is —R¹ or —(R²)_(m)—NR³R³ where —R¹ is a hydrocarbyl group, —R²— is a hydrocarbylene group, m is 0 or 1 or 2, and each —R³ is independently hydrogen or a hydrocarbyl group, so long as the —R¹, —R²—, and —R³ overall contain from 7 or even 9 to 40 carbon atoms combined. In some embodiments the substituted triazole of the invention is represented by Formula (X).

In some embodiments: n may be from 0 or 1 up to 4, 3, 2 or 1; R may be a hydrocarbyl group and may contain from 1 to 50 carbon atoms, or from 1 or 2 up to 40, 30, 20, 18 or even 8 carbon atoms, and in some embodiments contains 1 or 2 carbon atoms; within Y, m may be 0 or 1 or 2 and in some embodiments 1 or 2; R¹ may be a hydrocarbyl group and may contain from 1, 6, 10 or 12 up to 40, 30, 20, or even 18 carbon atoms; R² may be a hydrocarbylene group and may contain from 1, 6, 10 or 12 up to 40, 30, 20, 18, or even 8 carbon atoms or even 1 to 8 carbon atoms and in some embodiments contains 1 carbon atom; R³ may be hydrogen or a hydrocarbyl group and may contain from 1, 6, 10 or 12 up to 40, 30, 20, 18, or even 8 carbon atoms or even 1 to 8 carbon atoms and in some embodiments contains 8 carbon atoms, so long as Y contains from 8 to 40 carbon atoms.

In some embodiments —Y is —R¹, —R²—NHH, —R²—NHR³, —R²—NR³R³ where the various R groups can have any of definitions provided above again so long as the Y group contains overall 6 or 7 or even 9 up to 40 carbon atoms.

In some embodiments all of the hydrocarbyl groups described above are free of oxygen atoms. In some embodiments all of the hydrocarbyl groups described above are free of all heteroatoms and are purely alkyl groups except for a single nitrogen atom present in the Y group.

The substituted triazole of the invention may be prepared by condensing a basic triazole via its acidic —NH group with an aldehyde and an amine. In some embodiments the substituted triazole is the reaction product of a triazole, an aldehyde and an amine. Suitable triazoles that may be used to prepare the substituted triazole of the invention include benzotriazole, while suitable aldehydes include formaldehyde and reactive equivalents like formalin, while suitable amines include primary or secondary amines. In some embodiments the amines are secondary amines and further are branched amines. In still further embodiments the amines are beta-branched amines, for examples bis-2-ethylhexyl amine.

The metal deactivators may be present in the range from 0.001 to 0.1, from 0.01 to 0.04 or from 0.015 to 0.03 pbw of the lubricating oil composition. Metal deactivators may also be present in the composition from 0.002 or 0.004 to 0.02 pbw. The metal deactivator may be used alone or mixtures thereof.

INDUSTRIAL APPLICATION

The invention further provides a process for the preparation of lubricating oil compositions. The lubricating oil compositions are prepared by the steps comprising: a) mixing and/or dissolving in one another an antioxidant component that includes the combination of an alkylated diphenylamine, and a substituted hydrocarbyl mono-sulfide, a dispersant component which includes at least one of a polyetheramine, a borated succinimide dispersant, a non-borated succinimide dispersant, or a Mannich reaction product of a dialkylamine, an aldehyde and a hydrocarbyl substituted phenol. Optionally one or more additional additives may also be mixed into the oil. The materials are mixed until the additives are substantially or wholly dissolved, in some embodiments at elevated temperatures in the range 40° C. to 110° C., or 50° C. to 95° C., or even 55° C. to 85° C.; and for a period of time in the range 30 seconds to 24 hours, 2 minutes to 8 hours, or 5 minutes to 4 hours; and at pressures in the range 700 mm of Hg to 2000 mm of Hg, 750 mm of Hg to 900 mm of Hg, or 755 mm of Hg to 800 mm of Hg.

The order of addition of the additives is not overly limited. The optional additives may be mixed in at the same time as the other components or at a later time using any of the mixing procedures described above.

In some embodiments a portion of oil or similar diluent is present with the components and the components are mixed into the oil. In other embodiments a minimal amount of oil or diluent is present, other than that amount inherently present in the additive from their means of production and preparation and additional base oil is added after the component have been mixed. In any event the described processes results in lubricating compositions.

In some embodiments the lubricating oil compositions may be prepared from a concentrate comprising the steps of: a) mixing all of the components described above with minimal oil and/or diluent present, other than optionally some relatively small amount to allow for reasonable handling properties. The resulting concentrate may then be used in the preparation of a lubricating composition by mixing the concentrate with an effective amount of base oil or mixtures thereof resulting in a finished fluid. Optional additives may be added to the concentrate or to the resulting final fluid. These optional additives include any of those described above. In some embodiments these optional additives include a foam inhibitor, a demulsifier, a viscosity modifier, a pour point depressant, or mixtures thereof, and may be added such that they are present in the overall compositions in the range about 0, 0.01, 0.1 or even 0.25 or up to about 13, 10, 8 or even 6 pbw.

The compositions of the present invention may be used as industrial fluids, hydraulic fluids, turbine oils and circulating oils and combinations thereof. In some embodiments the compositions are used in steam and gas turbine systems. The use of the lubricating oil composition in such systems may prevent the formation of filter plugging deposits and sludge in turbines, or may provide at least one improved property selected from rust inhibition, oxidation inhibition and mixtures thereof. The invention further provides a lubricating oil composition that does not substantially react with zinc and/or calcium which may also prevent the formation of sludge and particulate material that accumulates, plugging the fine filters.

The invention further provides a method of lubricating a steam or gas turbine comprising the steps of supplying to said turbine any of the lubricating compositions described herein.

The invention further provides a method of improving the cleanliness of a steam or gas turbine comprising the steps of supplying to said turbine any of the lubricating compositions described herein. Operating the turbine with the described lubricating composition will result in improved cleanliness compared systems operated with conventional lubricants, particularly those formulated in Group II and Group III oils.

Specific Embodiment

The invention will be further illustrated by the following examples, which set forth particularly advantageous embodiments. While the examples are provided to illustrate the invention, they are not intended to limit it.

Comparative Example Set

Three comparative examples are prepared in order to better demonstrate the effects of the compositions of the present invention. These comparative examples are then included in each of the example sets below. As with all of the examples below, other additives are also present in the various formulations. While differences between example formulations are noted, full formulation details are not provided where they are not considered critical to the results of the testing and/or where the specific details are not believed to impact the results across samples.

Comparative Examples 1, 2 and 3 are each prepared in a blend of Group III base oils. This same blend of Group III base oils is used in the preparation of all of the examples described herein unless otherwise noted. All the formulations provided below are based on 100 pbw of the base oil. Comparative Examples 1, 2 and 3 also include a polyether demulsifier, an antiwear agent, an antifoam, and a metal deactivator. Comparative Examples 1 and 2 contain the same polyether demulsifier while Comparative Example 3 contains a different polyether demulsifier. Comparative Example 1 contains no dispersant, 0.375 pbw alkylated diphenyl amine antioxidant and 0.09 pbw substituted hydrocarbyl mono-sulfide. Comparative Example 2 contains no dispersant, 0.51 pbw alkylated diphenyl amine antioxidant, 0.09 pbw substituted hydrocarbyl mono-sulfide, and 0.12 pbw of a sterically hindered phenol antioxidant. Comparative Example 3 contains no dispersant, 0.775 pbw alkylated diphenyl amine antioxidant and 0.09 pbw substituted hydrocarbyl mono-sulfide. The formulation details and test results obtained for the comparative examples are included in the summary table below for each of the example sets.

Example Set 1

A set of examples is prepared where the formulations contain a polyetheramine dispersant. The tables below summarize these formulations, including the comparative formulations described above. Except for the differences noted in the tables and their footnotes, the formulations of the listed examples are substantially equivalent. The values in the tables are pbw.

TABLE 1-1 Details of Comparative Examples and Examples 1-A to 1-E Comp Comp Comp Ex Ex Ex Ex Ex Component Ex 1¹ Ex 2² Ex 3³ 1-A⁴ 1-B⁵ 1-C⁶ 1-D⁷ 1-E⁸ Base Oil Grp III Grp III Grp III Grp III Grp III Grp II Grp II Grp III Alkylated 0.375 0.510 0.775 0.375 0.375 0.375 0.375 0.775 Diphenylamine Subst Mono- 0.09 0.09 0.09 0.09 0.09 0.09 0.09 0.09 Sulfide Polyetheramine 0.0 0.0 0.0 0.1 0.5 0.5 0.5 0.5 Dispersant Borated 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Succinimide Non-Borated 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Succinimide Mannich 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Dispersant ¹Comparative Example 1 also contains a polyether demulsifier, an antiwear agent, an antifoam, and metal deactivator in conventional amounts, referred to below as Additive Package I. ²Comparative Example 2 also contains Additive Package I. ³Comparative Example 3 contains the same additives and the same amounts as those in Additive Package I except that the specific polyether demulsifier is different from that used in the other examples. This set of additives is referred to as Additive Package II below. ⁴Example 1-A also contains Additive Package I. ⁵Example 1-B also contains Additive Package I. ⁶Example 1-C also contains Additive Package I. ⁷Example 1-D also contains Additive Package I. ⁸Example 1-E also contains Additive Package II.

TABLE 1-2 Details of Examples 1-F to 1-M Ex Ex Ex Ex Ex Ex Ex Ex Component 1-F⁹ 1-G¹⁰ 1-H¹¹ 1-I¹² 1-J¹³ 1-K¹⁴ 1-L¹⁵ 1-M¹⁶ Base Oil Blend Grp III Grp III Grp III Grp III Grp III Grp III Grp III Grp II Alkylated 0.375 0.375 0.375 0.375 0.375 0.375 0.375 0.375 Diphenylamine Subst Mono- 0.09 0.09 0.09 0.09 0.09 0.09 0.09 0.09 Sulfide Polyetheramine 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.4 Dispersant Borated 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Succinimide Non-Borated 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Succinimide Mannich 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Dispersant ⁹Example 1-F also contains Additive Package II, as defined in Table 1-1 above. ¹⁰Example 1-G contains the polyether demulsifier and metal deactivator of Additive Package II but does not contain the antiwear agent or the antifoam. This set of additives is referred to as Additive Package III below. The example also contains a fatty carboxylic acid. ¹¹Example 1-H also contains Additive Package III and a fatty carboxylic ester. ¹²Example 1-I also contains Additive Package III and a sarcosine corrosion inhibitor. ¹³Example 1-J also contains Additive Package III and a fatty carboxylic ester. ¹⁴Example 1-K also contains Additive Package III and a sarcosine corrosion inhibitor. ¹⁵Example 1-L also contains Additive Package III and a fatty carboxylic acid but in a smaller amount that used in Example 1-G. ¹⁶Example 1-M also contains Additive Package I.

These examples are evaluated using ASTM D1401 to evaluate each sample's water separability performance and an internal thermal stability test.

For ASTM D1401, the test procedure involves a sample containing about 40 ml of the composition of the invention and about 40 ml of distilled water where the sample is stirred for about 5 minutes at about 54° C. in a graduated cylinder. The resulting mixture is then left to stand for about 30 minutes to allow a degree of separation of water and the composition of the invention to occur. The amount of separation is measured after every 5 minutes of the test. The results reported are based on X—Y—Z, where X indicates the amount of oil separated out, Y indicates the amount of water separated out and Z indicates the amount of oil and water still in an emulsion. The less time it takes for a sample to reach a reported result of 40-40-0, or a result roughly equivalent thereto, the better its performance.

The thermal stability test used for this testing involves placing standard sized copper and steel rods, after polishing and weighing, in a sample of the example formulation with the rods arranged so that they are in contact with one another at their midpoint (forming an X). The submerged rods are then held at 135° C.±1° C. for 168 hours. The rods are then rated for corrosion and weighed. The reported results for this test include the copper rod corrosion rating, the steel rod corrosion rating, and the amount of sludge generated which is determined by filtering a 100 mL portion of the oil, rinsing and drying the filter pad with any accumulated deposit; then weighing the dried filter paper and reported in mg per 100 ml. The corrosion ratings are on a scale of 1 to 10 with 1 being a freshly polished rod and 10 being a severely corroded rod. The lower the corrosion ratings and the lower the reported sludge, the better the performance of the sample.

The results of this testing are presented in the tables below. If no results are listed for a specific sample it indicates the sample was not tested by that method.

TABLE 1-3 Results for Comparative Examples and Examples 1-A to 1-E Comp Comp Comp Ex Ex Ex Ex Ex Test Method Ex 1 Ex 2 Ex 3 1-A 1-B¹⁷ 1-C 1-D 1-E D1401  0 min 0-0-80 0-0-80 0-0-80 0-0-80 0-0-80  5 min 12-6-62 26-22-32 10-0-70 5-5-70 1-25-54 10 min 36-36-8 29-40-1 35-26-20 35-30-15 40-40-0 15 min 40-40-0 40-40-0 40-40-0 40-40-0 20 min 25 min 30 min Therm Stability Copper Rating 3 5 4 3 3 4 4 Steel Rating 3 8 2 7 1 1 2 Sludge (mg/100 ml) 39.8 15.9 26.8 17.75 1.9 3.6 37.6 ¹⁷Example 1-B was tested three times using the D1401 method. In one instance the sample did not reach a 40-40-0 rating in 30 minutes. In one instance the sample reached a 40-40-0 rating in 15 minutes. In one instance the sample reached a 40-40-0 rating in 10 minutes. The middle result is reported in the table above and is expected to be a fair representation of the sample's performance.

TABLE 1-4 Results for Examples 1-F to 1-M Ex Ex Ex Ex Ex Ex Ex Ex Test Method 1-F 1-G 1-H 1-I 1-J 1-K 1-L 1-M D1401  0 min 0-0-80 0-0-80 0-0-80 0-0-80 0-0-80 0-0-80 0-0-80 0-0-80  5 min 37-39-4 38-40-2 10-2-68 2-25-53 7-0-73 1-0-79 2-0-78 35-35-10 10 min 38-40-2 40-40-0 29-20-31 2-27-51 30-27-23 1-0-79 4-0-76 39-40-1 15 min 39-40-1 40-40-0 3-28-49 40-40-0 1-0-79 7-11-62 39-40-1 20 min 39-40-1 5-30-45 1-0-79 7-20-53 39-40-1 25 min 39-40-1 9-30-41 1-0-79 30-38-12 39-40-1 30 min 39-40-1 19-32-29 1-0-79 38-38-4 39-40-1 Therm Stability Copper Rating 3 3 4 3 4 5 Steel Rating 1 1 1 1 2 1 Sludge (mg/100 ml) 3.7 19.5 2.8 3.4 1.7 2.8

The results show that the compositions of the invention give improved thermal stability protection while also maintaining acceptable water separability. In some embodiments the invention provides both improved thermal stability and water separability.

Example Set 2

A set of examples is prepared where the formulations contain a borated succinimide dispersant. The tables below summarize these formulations, including the comparative formulations described above. Except for the differences noted in the tables and their footnotes, the formulations of the listed examples are substantially equivalent. The values in the tables are pbw.

TABLE 2-1 Details of Comparative Examples and Examples 2-A to 2-E Comp Comp Comp Ex Ex Ex Ex Ex Component Ex 1¹ Ex 2² Ex 3³ 2-A⁴ 2-B⁵ 2-C⁶ 2-D⁷ 2-E⁸ Base Oil Grp III Grp III Grp III Grp III Grp III Grp III Grp III Grp III Alkylated 0.375 0.510 0.775 0.375 0.375 0.375 0.375 0.375 Diphenylamine Subst Mono- 0.09 0.09 0.09 0.09 0.09 0.09 0.09 0.09 Sulfide Polyetheramine 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Dispersant Borated 0.0 0.0 0.0 0.1 0.5 0.1 0.1 0.1 Succinimide Non-Borated 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Succinimide Mannich 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Dispersant ¹See details for Comparative Example 1 above. ²See details for Comparative Example 2 above. ³See details for Comparative Example 3 above. ⁴Example 2-A also contains Additive Package I, as defined above. ⁵Example 2-B also contains Additive Package I. ⁶Example 2-C also contains Additive Package I and a fatty carboxylic acid. ⁷Example 2-D also contains Additive Package I and a fatty carboxylic ester. ⁸Example 2-E also contains Additive Package I and a sarcosine corrosion inhibitor.

TABLE 2-2 Details of Examples 2-F to 2-H Ex Ex Ex Component 2-F⁹ 2-G¹⁰ 2-H¹¹ Base Oil Grp III Grp II Grp II Alkylated 0.375 0.375 0.375 Diphenylamine Subst Mono- 0.09 0.09 0.09 Sulfide Polyetheramine 0.0 0.0 0.0 Dispersant Borated 0.25 0.25 0.25 Succinimide Non-Borated 0.0 0.0 0.0 Succinimide Mannich 0.0 0.0 0.0 Dispersant ⁹Example 2-F also contains Additive Package I. ¹⁰Example 2-G also contains Additive Package I except that the level of metal deactivator in the package is reduced. ¹¹Example 2-H has the same additive package as Example 2-G.

These examples are evaluated using ASTM D1401 to evaluate each sample's water separability performance and an internal thermal stability test, as described in the sections above. The results of this testing are presented in the tables below. If no results are listed for a specific sample it indicates the sample was not tested by that method.

TABLE 2-3 Results for Comparative Examples and Examples 2-A to 2-E Comp Comp Comp Ex Ex Ex Ex Ex Test Method Ex 1 Ex 2 Ex 3 2-A 2-B 2-C 2-D 2-E D1401  0 min 0-0-80 0-0-80 0-0-80 0-0-80 0-0-80  5 min 2-0-78 1-0-79 5-5-70 30-22-28 0-27-53 10 min 4-9-67 1-0-79 40-40-0 40-40-0 0-37-43 15 min 4-36-40 1-0-79 41-39-0 20 min 40-40-0 1-0-79 41-39-0 25 min 1-0-79 41-39-0 30 min 1-0-79 41-39-0 Therm Stability Copper Rating 3 5 4 3 4 5 5 6 Steel Rating 3 8 2 1 1 1 1 1 Sludge (mg/100 ml) 39.8 15.9 26.8 0.1 0.5 0.1 5.2 1.1

TABLE 2-4 Results for Examples 2-F to 2-H Ex Ex Ex Test Method 2-F 2-G 2-H D1401  0 min 0-0-80 0-0-80 0-0-80  5 min 5-5-70 5-0-75 3-5-72 10 min 20-22-38 16-10-54 3-5-72 15 min 34-35-11 27-17-36 15-15-50 20 min 40-40-0 37-32-11 30-26-24 25 min 40-40-0 37-40-3 30 min 37-10-3 Therm Stability Copper Rating  5 Steel Rating  1 Sludge (mg/100 ml) 12.3

The results show that the compositions of the invention give improved thermal stability protection while also maintaining acceptable water separability. In some embodiments the invention provides both improved thermal stability and water separability.

Example Set 3

A set of examples is prepared where the formulations contain a non-borated succinimide dispersant. The tables below summarize these formulations, including the comparative formulations described above. Except for the differences noted in the tables and their footnotes, the formulations of the listed examples are substantially equivalent. The values in the tables are pbw.

TABLE 3-1 Details of Comparative Examples and Examples 3-A to 3-E Comp Comp Comp Ex Ex Ex Ex Ex Component Ex 1¹ Ex 2² Ex 3³ 3-A⁴ 3-B⁵ 3-C⁶ 3-D⁷ 3-E⁸ Base Oil Grp III Grp III Grp III Grp III Grp III Grp III Grp III Grp III Alkylated 0.375 0.510 0.775 0.375 0.375 0.775 0.775 0.375 Diphenylamine Subst Mono- 0.09 0.09 0.09 0.09 0.09 0.09 0.09 0.09 Sulfide Polyetheramine 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Dispersant Borated 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Succinimide Non-Borated 0.0 0.0 0.0 0.1 0.5 0.5 0.5 0.5 Succinimide Mannich 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Dispersant ¹See details for Comparative Example 1 above. ²See details for Comparative Example 2 above. ³See details for Comparative Example 3 above. ⁴Example 3-A also contains Additive Package I, as defined above. ⁵Example 3-B also contains Additive Package I. ⁶Example 3-C also contains Additive Package II, as defined above. ⁷Example 3-D also contains Additive Package II and a fatty carboxylic acid. ⁸Example 3-E also contains Additive Package I and a sarcosine corrosion inhibitor.

TABLE 3-2 Details of Examples 3-F to 3-J Ex Ex Ex Ex Ex Component 3-F⁹ 3-G¹⁰ 3-H¹¹ 3-I¹² 3-J¹³ Base Oil Grp III Grp III Grp III Grp III Grp III Alkylated 0.775 0.775 0.375 0.375 0.375 Diphenylamine Subst Mono- 0.09 0.09 0.09 0.09 0.09 Sulfide Polyetheramine 0.0 0.0 0.0 0.0 0.0 Dispersant Borated 0.0 0.0 0.0 0.0 0.0 Succinimide Non-Borated 0.5 0.25 0.25 0.1 0.5 Succinimide Mannich 0.0 0.0 0.0 0.0 0.0 Dispersant ⁹Example 3-F also contains the antifoam, polyether demulsifier, and metal deactivator of Additive Package II, as defined above, but does not contain the antiwear agent. This set of additives is referred to as Additive Package IV below. The example also contains a fatty carboxylic acid but at a lower level than Example 3-D. ¹⁰Example 3-G contains Additive Package IV and also contains a fatty carboxylic acid at the same level as Example 3-D. ¹¹Example 3-H also Additive Package I and a sarcosine corrosion inhibitor. ¹²Example 3-I also contains Additive Package I and the non-borated succinimide dispersant has a higher molecular weight than that used on the other examples. ¹³Example 3-J also contains Additive Package I and uses the higher molecular weight non-borated succinimide dispersant of Example 3-I.

These examples are evaluated using ASTM D1401 to evaluate each sample's water separability performance and an internal thermal stability test, as described in the sections above. The results of this testing are presented in the tables below. If no results are listed for a specific sample it indicates the sample was not tested by that method.

TABLE 3-3 Results for Comparative Examples and Examples 3-A to 3-E Comp Comp Comp Ex Ex Ex Ex Ex Test Method Ex 1 Ex 2 Ex 3 3-A 3-B 3-C 3-D 3-E D1401  0 min 0-0-80 0-0-80 0-0-80 0-0-80  5 min 0-5-75 0-0-80 0-0-80 2-0-78 10 min 40-40-0 0-3-77 0-0-80 30-23-27 15 min 23-30-27 10-15-55 39-40-1 20 min 40-40-0 36-32-12 40-40-1 25 min 39-40-1 30 min 40-40-0 Therm Stability Copper Rating 3 5 4 3 3 3 7 4 Steel Rating 3 8 2 1 1 1 1 1 Sludge (mg/100 ml) 39.8 15.9 26.8 0.6 1.1 7.5 2.4 3.3

TABLE 3-4 Results for Examples 3-F to 3-J Ex Ex Ex Ex Ex Test Method 3-F 3-G 3-H 3-I 3-J D1401  0 Min 0-0-80 0-0-80  5 min 2-12-66 0-0-80 10 min 5-32-43 1-0-79 15 min 40-40-0 1-0-79 20 min 1-0-79 25 min 1-0-79 30 min 1-0-79 Therm Stability Copper Rating 4 4 4 Steel Rating 1 1 1 Sludge (mg/100 ml) 0.4 8.0 0.1

The results show that the compositions of the invention give improved thermal stability protection while also maintaining acceptable water separability. In some embodiments the invention provides both improved thermal stability and water separability.

Example Set 4

A set of examples is prepared where the formulations contain a Mannich reaction product of a dialkylamine, an aldehyde and a hydrocarbyl substituted phenol. The tables below summarize these formulations, including the comparative formulations described above. Except for the differences noted in the tables and their footnotes, the formulations of the listed examples are substantially equivalent. The values in the tables are pbw.

TABLE 4-1 Details of Comparative Examples and Examples 4-A to 4-B Comp Comp Comp Ex Ex Component Ex 1¹ Ex 2² Ex 3³ 3-A⁴ 3-B⁵ Base Oil Grp III Grp III XGrp III Grp III Grp III Alkylated 0.375 0.510 0.775 0.375 0.375 Diphenylamine Subst Mono- 0.09 0.09 0.09 0.09 0.09 Sulfide Polyetheramine 0.0 0.0 0.0 0.0 0.0 Dispersant Borated 0.0 0.0 0.0 0.0 0.0 Succinimide Non-Borated 0.0 0.0 0.0 0.0 0.0 Succinimide Mannich 0.0 0.0 0.0 0.1 0.5 Dispersant ¹See details for Comparative Example 1 above. ²See details for Comparative Example 2 above. ³See details for Comparative Example 3 above. ⁴Example 4-A also contains Additive Package I, as defined above. ⁵Example 4-B also contains Additive Package I.

These examples are evaluated using ASTM D1401 to evaluate each sample's water separability performance and an internal thermal stability test, as described in the sections above. The results of this testing are presented in the tables below. If no results are listed for a specific sample it indicates the sample was not tested by that method.

TABLE 4-2 Results for Comparative Examples and Examples 4-A to 4-B Comp Comp Comp Ex Ex Test Method Ex 1 Ex 2 Ex 3 4-A 4-B D1401  0 min 0-0-80  5 min 34-34-12 10 min 39-40-1 15 min 40-40-0 20 min 25 min 30 min Therm Stability Copper Rating 3 5 4 4 Steel Rating 3 8 2 4 Sludge (mg/100 ml) 39.8 15.9 26.8 14.0

The results show that the compositions of the invention give improved thermal stability protection while also maintaining acceptable water separability. In some embodiments the invention provides both improved thermal stability and water separability.

While the invention has been explained, it is to be understood that various modifications thereof will become apparent to those skilled in the art upon reading the specification. Therefore, it is to be understood that the invention disclosed herein is intended to cover such modifications as fall within the scope of the appended claims.

In this specification the terms “hydrocarbyl substituent” or “hydrocarbyl group,” as used herein are used in their ordinary sense, which is well-known to those skilled in the art. Specifically, they refer to a group primarily composed of carbon and hydrogen atoms that is attached to the remainder of the molecule through a carbon atom and does not exclude the presence of other atoms or groups in a proportion insufficient to detract from the molecule having a predominantly hydrocarbon character. In general, no more than two, preferably no more than one, non-hydrocarbon substituent will be present for every ten carbon atoms in the hydrocarbyl group; typically, there will be no non-hydrocarbon substituents in the hydrocarbyl group. A more detailed definition of the terms “hydrocarbyl substituent” or “hydrocarbyl group,” is described in U.S. Pat. No. 6,583,092.

Each of the documents referred to above is incorporated herein by reference. Except in the Examples, or where otherwise explicitly indicated, all numerical quantities in this description specifying amounts of materials, reaction conditions, molecular weights, number of carbon atoms, and the like, are to be understood as modified by the word “about.” Unless otherwise indicated, all percent and formulation values listed herein are on a weight basis. Unless otherwise indicated, each chemical or composition referred to herein should be interpreted as being a commercial grade material which may contain the isomers, by-products, derivatives, and other such materials which are normally understood to be present in the commercial grade. However, the amount of each chemical component is presented exclusive of any solvent or diluent, which may be customarily present in the commercial material, unless otherwise indicated. It is to be understood that the upper and lower amount, range, and ratio limits set forth herein may be independently combined. Similarly, the ranges and amounts for each element of the invention can be used together with ranges or amounts for any of the other elements. As used herein, the expression “consisting essentially of” permits the inclusion of substances that do not materially affect the basic and novel characteristics of the composition under consideration. 

What is claimed is:
 1. A lubricating oil composition comprising: a) an oil of lubricating viscosity comprising a Group II base oil, a Group III base oil, or combinations thereof; b) an antioxidant component comprising: (i) an alkylated diphenylamine, and (ii) a substituted hydrocarbyl mono-sulfide; c) a dispersant component comprising at least one of: (i) a polyetheramine, (ii) a borated succinimide dispersant, (iii) a non-borated succinimide dispersant, and (iv) a Mannich reaction product of a dialkylamine, an aldehyde and a hydrocarbyl substituted phenol and d) optionally one or more additional additives; wherein component b) is present in the overall composition from 0.4 to 0.9 parts by weight; and wherein the substituted hydrocarbyl mono-sulfides are represented by the formula:

wherein R³ is a saturated or unsaturated branched or linear alkyl group with about 10 to about 15 carbon atoms; R⁴, R⁵, R⁶ and R⁷ are independently hydrogen or alkyl containing about 1 to about 3 carbon atoms; wherein: (I) the dispersant component comprises a polyetheramine derived from the reaction of a mixture of alcohols containing from 10 to 15 carbon atoms, an alkoxylate and an amine; wherein the antioxidant component is present in the overall composition at less than 0.865 parts by weight; wherein the composition is free of N-alkyl sarcosines; wherein the composition contains less than 0.1 parts by weight of fatty carboxylic acids; and wherein the dispersant component is present in the overall composition from 0.07 to 0.4 parts by weight; (II) the dispersant component comprises a borated succinimide dispersant derived from polyisobutylene having a number average molecular weight from 500 to 3000 and polyethylenepolyamines; wherein the dispersant component is present in the overall composition from 0.07 to less than 0.4 parts by weight; (III) the dispersant component comprises a non-borated succinimide dispersant derived from polyisobutylene having a number average molecular weight from 500 to 3000 and polyethylenepolyamines; wherein the composition contains less than 0.1 parts by weight of fatty carboxylic acids; and wherein the dispersant component is present in the overall composition from 0.06 to 0.35 parts by weight; or (IV) the dispersant component comprises a Mannich reaction product derived from the reaction of a dialkylamine, formaldehyde, and a polyisobutylene substituted phenol where the polyisobutylene has a number average molecular weight from 500 to 3000; and wherein the dispersant component is present in the overall composition from 0.07 to 0.44 parts by weight.
 2. The composition of claim 1 wherein component d) comprises a rust inhibitor, a metal deactivator, a demulsifier, an antifoam agent, or combinations thereof.
 3. The composition of claim 2 wherein the rust inhibitor comprises an amine phosphate, a fatty carboxylic acid or ester thereof, an ester of a nitrogen-containing carboxylic acid, an ammonium sulfonate, an imidazoline, or combinations thereof; wherein the metal deactivator comprises a triazole, a tolyltriazole, a thiadiazole, or combinations thereof; wherein the demulsifier comprises a polyether; and wherein the antifoam comprises an acrylate copolymer.
 4. The composition of claim 1, wherein the alkylated diphenylamine is represented by the formula:

wherein R¹ and R² are independently a hydrogen or an alkyl group containing about 5 to 20 carbon atoms; or a linear or branched alkyl group containing 1 to 24 carbon atoms and q and r are each independently 0, 1, 2, or 3, provided that the sum of q and r is at least one.
 5. The composition of claim 1, wherein the substituted hydrocarbyl monosulfide is n-dodecyl 2-hydroxyethyl sulfide, 1-(tert-dodecylthio)-2-propanol, or mixtures thereof.
 6. The lubricating composition of claim 2, wherein the metal deactivator is selected from the group comprising hydrocarbyl substituted benzotriazole, 5-methylbenzotriazole and mixtures thereof.
 7. The composition of claim 1, wherein the additive components b) to d) are in the range about 0 to about 13 parts by weight of the overall composition.
 8. The composition of claim 1 wherein: (I) the dispersant component comprises a polyetheramine derived from the reaction of a mixture of alcohols containing from 10 to 18 carbon atoms, an alkoxylate and an amine; wherein the antioxidant component is present in the overall composition at less than 0.865 parts by weight; wherein the composition is free of N-alkyl sarcosines; wherein the composition contains less than 0.1 parts by weight of fatty carboxylic acids; and wherein the dispersant component is present in the overall composition from 0.07 to 0.4 parts by weight.
 9. The composition of claim 1 wherein: (II) the dispersant component comprises a borated succinimide dispersant derived from polyisobutylene having a number average molecular weight from 500 to 3000 and polyethylenepolyamines; wherein the dispersant component is present in the overall composition from 0.07 to less than 0.4 parts by weight.
 10. The composition of claim 1 wherein: (III) the dispersant component comprises a non-borated succinimide dispersant derived from polyisobutylene having a number average molecular weight from 500 to 3000 and polyethylenepolyamines; wherein the composition contains less than 0.1 parts by weight of fatty carboxylic acids; and wherein the dispersant component is present in the overall composition from 0.06 to 0.35 parts by weight.
 11. The composition of claim 1 wherein: (IV) the dispersant component comprises a Mannich reaction product derived from the reaction of a dialkylamine, formaldehyde, and a polyisobutylene substituted phenol where the polyisobutylene has a number average molecular weight from 500 to 3000; and wherein the dispersant component is present in the overall composition from 0.07 to 0.44 parts by weight.
 12. A process to prepare a lubricating oil composition comprising the steps of: (I) mixing together: a) an oil of lubricating viscosity comprising a Group II base oil, a group III base oil, or combinations thereof; b) an antioxidant component comprising: (i) an alkylated diphenylamine, and (ii) a substituted hydrocarbyl mono-sulfide; c) a dispersant component comprising at least one of: (i) a polyetheramine, (ii) a borated succinimide dispersant, (iii) a non-borated succinimide dispersant, and (iv) a Mannich reaction product of a dialkylamine, an aldehyde and a hydrocarbyl substituted phenol; and d) optionally other additives; wherein component b) is present in the overall composition from 0.4 to 0.9 parts by weight; and wherein the substituted hydrocarbyl mono-sulfides are represented by the formula:

wherein R³ is a saturated or unsaturated branched or linear alkyl group with about 10 to about 15 carbon atoms; R⁴, R⁵, R⁶ and R⁷ are independently hydrogen or alkyl containing about 1 to about 3 carbon atoms; wherein: (I) the dispersant component comprises a polyetheramine derived from the reaction of a mixture of alcohols containing from 10 to 18 carbon atoms, an alkoxylate and an amine; wherein the antioxidant component is present in the overall composition at less than 0.865 parts by weight; wherein the composition is free of N-alkyl sarcosines; wherein the composition contains less than 0.1 parts by weight of fatty carboxylic acids; and wherein the dispersant component is present in the overall composition from 0.07 to 0.4 parts by weight; (II) the dispersant component comprises a borated succinimide dispersant derived from polyisobutylene having a number average molecular weight from 500 to 3000 and polyethylenepolyamines; wherein the dispersant component is present in the overall composition from 0.07 to less than 0.4 parts by weight; (III) the dispersant component comprises a non-borated succinimide dispersant derived from polyisobutylene having a number average molecular weight from 500 to 3000 and polyethylenepolyamines; wherein the composition contains less than 0.1 parts by weight of fatty carboxylic acids; and wherein the dispersant component is present in the overall composition from 0.06 to 0.35 parts by weight; or (IV) the dispersant component comprises a Mannich reaction product derived from the reaction of a dialkylamine, formaldehyde, and a polyisobutylene substituted phenol where the polyisobutylene has a number average molecular weight from 500 to 3000; and wherein the dispersant component is present in the overall composition from 0.07 to 0.44 parts by weight.
 13. The process of claim 12, wherein the antioxidant package is in the range of 0.05 to 13 parts by weight of the overall composition; the dispersant component is in the range of 0.05 to 10 parts by weight of the overall composition; the optional additives, when present, are present from 0.001 to 10 parts by weight of the overall composition; and the balance is made up of the oil of lubricating viscosity.
 14. The process of claim 12 wherein: (I) the dispersant component comprises a polyetheramine derived from the reaction of a mixture of alcohols containing from 10 to 18 carbon atoms, an alkoxylate and an amine; wherein the antioxidant component is present in the overall composition at less than 0.865 parts by weight; wherein the composition is free of N-alkyl sarcosines; wherein the composition contains less than 0.1 parts by weight of fatty carboxylic acids; and wherein the dispersant component is present in the overall composition from 0.07 to 0.4 parts by weight.
 15. The process of claim 12 wherein: (II) the dispersant component comprises a borated succinimide dispersant derived from polyisobutylene having a number average molecular weight from 500 to 3000 and polyethylenepolyamines; wherein the dispersant component is present in the overall composition from 0.07 to less than 0.4 parts by weight.
 16. The process of claim 12 wherein: (III) the dispersant component comprises a non-borated succinimide dispersant derived from polyisobutylene having a number average molecular weight from 500 to 3000 and polyethylenepolyamines; wherein the composition contains less than 0.1 parts by weight of fatty carboxylic acids; and wherein the dispersant component is present in the overall composition from 0.06 to 0.35 parts by weight.
 17. The process of claim 12 wherein: (IV) the dispersant component comprises a Mannich reaction product derived from the reaction of a dialkylamine, formaldehyde, and a polyisobutylene substituted phenol where the polyisobutylene has a number average molecular weight from 500 to 3000; and wherein the dispersant component is present in the overall composition from 0.07 to 0.44 parts by weight. 